Such helmets held Dairy Queen ice cream. I am confident that other ice cream companies, offered the same promotion, as did the individual major and minor league parks.

These are older helmets, thus I'll identify the teams, left to right: Houston Astros, Montreal Expos (now the Washington Nationals), and the Pittsburgh Pirates. From the color schemes, I'd think that these were from the 70s. Correct me if I'm incorrect...thanks!